3 letters:
bok, doc, hoc, hok, kok, lok, mok, och, roc, sok, wok

4 letters:
bach, balk, bloc, blok, boch, bock, broc, brok, calk, chok, cock, croc, dock, falk, floc, gawk, haak, hauk, hawk, hoch, hock, iraq, jock, kalk, kauk, kloc, kock, kroc, krok, kwok, loch, lock, mach, mauk, moch, mock, nock, poch, pock, roch, rock, salk, sauk, skok, sock, talk, tock, valk, vlok, walk, zoch

5 letters:
aatcc, adhoc, alloc, asroc, baack, balkh, baulk, bloch, block, broch, brock, byacc, capoc, caulk, ceroc, chalk, chauk, chock, ciroc, clock, coloc, crock, d-loc, docke, drawk, drock, estok, falke, faulk, flock, fnmoc, frock, fyock, g-loc, glauc, glock, gocke, groch, grock, haack, haake, hauck, hauke, hawke, hla-c, hocke, hurok, isaak, issaq, izaak, jfacc, jrock, jrotc, jspoc, kalok, kdloc, klock, knaak, knock, krock, laack, laake, lauck, locke, lokke, m-lok, maack, maroc, mauck, medoc, miwok, mock-, modok, ntalk, obrok, ploch, plock, proch, prock, raakh, raroc, rocke, rokke, schok, scroc, shaak, shock, smaak, smock, socke, spaak, spock, sproc, srock, stalk, stock, swalk, t-loc, taake, talaq, taroc, troch, uraqt, vanoc, vocke, waack, wache, walke, waulk, xtalk, ytalk, zwack

6 letters:
accroc, actalk, ad-hoc, adcock, ad hoc, alcock, amarok, arawak, arrach, arzach, asrock, auroch, barach, baykok, bn toc, bodach, bohlke, capoch, d-lock, defalk, edraak, elcock, enlock, epiroc, eriach, erlach, escroc, flocke, geoloc, glocke, gohlke, guache, haacke, ijiraq, inlock, istock, karzok, klocke, knaack, knokke, lekach, lohoch, lohock, luwack, manioc, maniok, mlotok, mohawk, njrotc, nurock, oclock, orrach, padauk, pandoc, pathak, penock, pflock, playok, qstock, rhebok, rocque, sa-roc, schalk, schoch, schock, shlock, shrock, skroch, sprock, squawk, staack, stocke, stockx, stokke, strock, synroc, tanakh, thwack, umbach, uncock, undock, unisoc, unlock, uptalk

7 letters:
30 rock, ad-rock, adblock, airlock, al-iraq, allcock, angakok, ansbach, anspach, antioch, armlock, ashlock, bambach, bangkok, baraque, bawcock, bedrock, beldock, bierock, biorock, biztalk, blakroc, boocock, bostock, by-talk, by-walk, c-block, caprock, carlock, casaque, catwalk, chepauk, cosaque, cumdach, d-block, dadrock, daglock, dambach, dc talk, dectalk, defrock, destock, doglock, dorhawk, dundalk, ebrauke, einfach, elflock, en bloc, eshbach, eurovoc, f-block, fetlock, g-shock, gablock, genlock, glauque, gondioc, goshawk, gourock, gunlock, hadiach, hamrock, hancock, harbach, haslock, havelok, haycock, haydock, hemlock, hoolock, jacques, jashawk, jaywalk, kalbach, kedlock, korokke, kowalke, laibach, laubach, laycock, leacock, leglock, limbach, macaque, madlock, mandioc, marbach, matlock, maybach, maycock, meacock, merauke, meshach, montauk, movie4k, mudrock, netrock, newyacc, niblock, nisroch, norwalk, o'clock, oarlock, outtalk, outwalk, padlock, paltalk, peacock, petcock, pibroch, pitcock, poptalk, postdoc, protalk, putlock, rayrock, restock, rombach, rowlock, salzach, schaack, schlock, schrock, seacock, seahawk, sealock, seebach, shobach, shylock, skyhawk, skywalk, songkok, subhlok, taglock, tatlock, teremok, torgoch, unblock, unfrock, unstock, warlock, wedlock, wenlock, wikiloc, winlock, yeosock, zamrock

8 letters:
air lock, air sock, alt-rock, antilock, antioche, babytalk, backtalk, ballcock, ballhawk, baumbach, beadlock, bedstock, benstock, bernbach, bierbalk, binstock, bioshock, bitstock, boondock, brumbach, buntrock, cakewalk, calstock, chhapaak, cincalok, cinemark, clarsach, coldcock, comstock, cooltalk, darkhawk, deadlock, deathlok, dethklok, devilock, diestock, dingtalk, disfrock, donsbach, dorrhawk, dresbach, dry dock, duckwalk, echohawk, eisenach, eschbach, everbach, eyestalk, fatstock, fauxhawk, feshbach, finfrock, fishhawk, folkrock, forehock, gamecock, gavelock, goldbach, goonrock, greyhawk, gridlock, grimlock, gritrock, gunstock, h-blockx, halfcock, handcock, hardrock, hardtalk, havelock, haystalk, headlock, heimbach, heinbach, hen hawk, herblock, honestok, iceblock, incabloc, inukjuak, jokkmokk, kazachok, kidstock, kuujjuaq, landlock, leimbach, leinbach, leverock, lifelock, linstock, lisptalk, listproc, livelock, lovelock, mackinac, maniaque, mansbach, mindwalk, minirock, monobloc, moonrock, moonwalk, newshawk, no-knock, overlock, overtalk, overwalk, pandadoc, penstock, picklock, pop rock, portlock, post hoc, psylocke, qaqortoq, racewalk, rebstock, rendrock, roborock, ropewalk, sandbach, sandrock, seelbach, shamrock, shedlock, sherlock, sheshach, shiprock, sidelock, sidewalk, sillcock, slutwalk, soaprock, sob rock, sparhawk, spinlock, spurlock, stab-lok, starhawk, staubach, stopcock, sunblock, swagelok, teletalk, tipstock, tomahawk, toontalk, traprock, turncock, vanscyoc, warloeck, war hawk, waterbok, weinbach, weisbach, westrock, wheelock, whitlock, witbrock, woodcock, woodlock, woolcock

9 letters:
anti-lock, antiknock, appletalk, arschloch, azederach, baby talk, back-talk, bad block, ball cock, ball hawk, basilicok, beanstalk, bergstock, bienstock, billycock, blackcock, blackhawk, blacklock, blackrock, blakelock, bloodrock, boardwalk, breadtalk, brecknock, breitbach, brevibloc, buttstock, cardstock, cellblock, cindytalk, cold-cock, colestock, cornstalk, crip walk, crosstalk, crosswalk, deadstock, dreadlock, dreisbach, dualshock, eaglehawk, ethertalk, fast-talk, feedstock, feschbach, feuerbach, finefrock, fischbach, fish hawk, flintlock, folk-rock, footstalk, footstock, foreshock, glam rock, glasscock, goldstock, grauwacke, graywacke, greywacke, haithcock, half-cock, headstock, heartlock, hedgecock, hemiblock, hitchcock, hollyhock, hot stock, hypertalk, idle talk, interlock, intertalk, jazz-rock, kakaotalk, kittyhawk, klopstock, krautrock, ladyclock, ladyhawke, leafstalk, lintstock, livestock, localtalk, makeblock, maraviroc, marschalk, massbauch, matchlock, mollymawk, monotroch, nanoblock, nawaiwaqt, nighthawk, overclock, overstock, peerblock, pinchcock, plaintalk, poppycock, post-rock, punk rock, rackarock, roadblock, roostcock, rootstalk, rootstock, rosenbach, sash lock, sasl-yacc, sassenach, schupbach, schwebach, seedstock, self-talk, shacklock, sheepwalk, sheetrock, shop talk, skirlcock, slapshock, sleepwalk, slickrock, smalltalk, soap-rock, sour dock, spacewalk, steinbach, steinbock, stonerock, stopclock, stormcock, supertalk, tailblock, tailstock, timeclock, top-block, twistlock, underlock, wall rock, weighlock, weinstock, wheellock, whipstalk, whipstock, whitelock, wind sock, wittstock, woodblock, woodshock, woodstock, woolstock, wristlock

10 letters:
afflerbach, aftershock, allensbach, angry walk, avant-rock, beef stock, bill block, blackstock, black cock, bloodstock, blues-rock, bridgetalk, buntstrock, castlerock, chalk talk, city block, cnwch coch, corn-stalk, cross-talk, dance-rock, dandy-cock, doubletalk, drillstock, eagle-hawk, earthshock, emery rock, empty talk, fahnestock, fairy-lock, falkenbach, fetterlock, fish-block, gengenbach, haigerloch, half-stock, hammerlock, hassebrock, hollerbach, hover-hawk, intershock, john locke, katzenbach, khabarnaak, kilmarnock, kirk/spock, lever lock, line block, marsaxlokk, marsh hawk, maya hawke, molly-mawk, muehlebach, night-hawk, paddlecock, peter falk, rosenstock, sales talk, scalp lock, schwalbach, seed stock, shellshock, shinnecock, shite-hawk, small talk, space walk, spatchcock, spitchcock, streetwalk, suckanhock, superblock, sweat sock, sweet-talk, sweet talk, synth-rock, table talk, take stock, thricecock, time clock, tool-stock, trap block, trash-talk, understock, vapor-lock, vapor lock, waffenrock, wall clock, weizenbock, wheel lock, winterhawk, wood block, yolk-stalk, young rock, zellerbach

11 letters:
alarm clock, beetlestock, bienenstock, birkenstock, bitcointalk, bitter dock, breechblock, chickenhawk, chockablock, cinderblock, double-lock, double-talk, double talk, escape cock, gapingstock, gazingstock, gwenhwyfach, heart block, hieromonach, joint-stock, jungle cock, little-rock, little rock, living rock, ma'alefa'ak, marita koch, muschelkalk, one ok rock, penny stock, pigeon hawk, reichenbach, rudderstock, safety lock, shell shock, shittlecock, shuttlecock, smock-frock, sparrowhawk, street-walk, tower block, turkey-cock, turkey cock, water clock, weathercock, window lock, winkle-hawk, yellow dock

12 letters:
12 'o' clock, atomic clock, bel-merodach, bendlerblock, breeze-block, bretman rock, cam-in-block, caudal block, chicken hawk, cinder block, common stock, counterstock, crushed rock, cuckoo clock, damper block, electroshock, engine block, fensterstock, flower stalk, four o'clock, french chalk, genesis rock, growth stock, igneous rock, john hancock, ken shamrock, lady's smock, letter stock, matt hancock, max whitlock, mental block, mockingstock, office block, pillar-block, pillow block, prairie dock, pulley-block, push-to-talk, sarah chalke, shutterstock, skeeter hawk, snatch block, sondra locke, sparrow hawk, sponsorblock, square block, system clock, turret clock, varsity sock, voting stock, widow's walk

13 letters:
12-hour clock, 24-hour clock, ammonia clock, athletic sock, auction block, black hemlock, bone tomahawk, bullock block, butcher-block, butcher block, capital stock, chicken stock, chock-a-block, control stock, cooper's hawk, cylinder lock, dousing-chock, drawing chalk, evil-merodach, fighting cock, floating dock, ignition lock, insulin shock, laughingstock, malcolm stock, marianne koch, mosquito hawk, noah baumbach, nordwestblock, off-the-clock, plutonic rock, plymouth rock, pointingstock, quarter stock, rolling stock, sterling bloc, volcanic rock, wahunsonacock, watered stock, water hemlock

14 letters:
allison stokke, anderson .paak, building block, chaparral cock, chopping block, cylinder block, electric clock, electric shock, graham hancock, karun chandhok, laughing-stock, lesser hemlock, nortonlifelock, nunsexmonkrock, out-of-wedlock, out of wedlock, pendulum clock, podvorotnichok, poison hemlock, school of rock, starting block, treasury stock, unlisted stock, virginia stock, water shamrock, wild hollyhock, writer's block

15 letters:
capital of iraq, christina haack, douglas hemlock, eastern hemlock, monchengladbach, pacific hemlock, preferred stock, round-the-clock, round the clock, scotch woodcock, spotted hemlock, stumbling-block, stumbling block, vincent hancock, virginian stock, western hemlock

16 letters:
around-the-clock, around the clock, authorized stock, biological clock, canadian hemlock, carolina hemlock, classified stock, cock-of-the-rock, cock of the rock, combination lock, electrical shock, kangiqsualujjuaq, mercedes-maybach, metamorphic rock, mountain hemlock, munchen-gladbach, porphyritic rock, reacquired stock, scribbling block, sedimentary rock, shepherd's clock

17 letters:
against the clock, american woodcock, bergisch-gladbach, eurasian woodcock, floating dry dock, grandfather clock, jack-of-the-clock, obstructive shock, villeneuve-d'ascq

18 letters:
distributive shock, mountain hollyhock, record of ragnarok, sweet four o'clock, west coast hemlock

19 letters:
boeing t-7 red hawk, concurrentsmalltalk, desert four o'clock, douglas a-4 skyhawk

20 letters:
curtiss p-40 warhawk, saxe-weimar-eisenach

21 letters:
2003 invasion of iraq, colorado four o'clock, johann sebastian bach, mountain four o'clock, new kids on the block, spotted water hemlock, trailing four o'clock

22 letters:
over the counter stock, sikorsky sh-60 seahawk

23 letters:
california four o'clock

24 letters:
lockheed f-117 nighthawk

25 letters:
sikorsky uh-60 black hawk